Pontoon bridge support



June 13, 1950 J. w. BERETTA PONTOON BRIDGE SUPPORT 5 SheetsSheet 1 FiledSept. 24, 1946 8111mm for June 13, 1950 J. w. BERETI A' PONTOON BRIDGESUPPORT 5 Shee ts-Sheet 2 Filed Sept. 24, 1946 1 2 15 1 2 15 Ill: 15 8 JIan Z0 ref/a,

m as June 13, 1950 J. w. BERETTA 2,510,948

PONTOON BRIDGE SUPPORT Filed Sept. 24, 1946 5 Sheets-Sheet 3 5 Snowdrop5 Sheets-Sheet 4 nventor fll'l'orucqo I I I I i J. W. BERETTA PONTOONBRIDGE SUPPORT llllllllrllllll Filed Sept. 24, 1946 Fig.10.

June 13, 1950 June 13, 1950 J. w. BERETTA PONTOON BRIDGE SUPPORT 5Sheets-Sheet 5' Filed Sept. 24, 1946 ef/cb I rm atrornm a Patented June13, 1950 UNITED STATES PATENT OFFICE PONTOON BRIDGE SUPPORT John W.Beretta, San Antonio, Tex.

Application September 24, 1946, Serial N 0. 699,070

15 Claims. (01. 14-27) (Granted under the act of March 3, 1883, asamended April 30, 1928; 370 O. G. 757) Theinvention described herein maybe manufactured and used by or for the Government for governmentalpurposes, without payment to me of any royalty thereon.

This invention relates to bridges, more particularly it is directed tothe shore connection of a floating bridge structure.

In floating bridges, particularly those of a military nature, it hasbeen customary to connect the floating section of the bridge with thebank by a short connection consisting of trestle-supported sections, thenumber of sections being dependent upon the depth of water and otherinshore conditions. The trestle next to the inshore boat of the floatingsection is connected to the floating section by a hinge span, and likethe other trestles, consists of a transom fixedly connected to columnssupported by mud shores or th like. This type of connection issatisfactory in a low capacity bridge having a flooring system of thebalk and chess type but has the Weakness that the entire load comingonto the floating section is thrown on the end span of that section as aconcentrated load with the result that it is difficul to get enoughfloating support under that portion of the bridge. In a new type of highcapacity floating bridge now coming into use a flooring system of hollowbeams is used in lieu of the earlier balk and chess decking and thedifliculties inherent in the hinge span connection of the earlier bridgereferred to above are avoided by projecting the beams beyond the inshoreboat to the first transom of the shore connection. It has been found,however, that when a heavy load passes over the bridge the beams in thespan between inshore boat and its adjacent transom are overstressed dueto the fact that the transom is relatively fixed While the inshore boatssink deeper into the water as the load passes over them. With this inmind, and in accordance with a feature of my invention, means are providd for permitting heightwise movement of the flooring at the transomsupport concomitantly with the heightwise movement of the adjacentinshore boats. As illustrated, this means consists of a transom fixedlyconnected to supporting columns, a floor supporting member located abovethe transom and yieldable means interconnecting the transom andsupporting member arranged to permit heightwise movement of the floorsupporting member as the load passes over it.

A further object of the invention is to provide a floating bridgestructure including yielding supports at the end of the floating portionof the ponton bridge, using trestle supports, which will I enable theuse of a continuous span of bridge flooring between the last ponton andthe first trestle support.

Another object of the invention is to provid a yielding support for a.ponton bridge which may b incorporated on top of the transom of atrestle support adjoining each of the ends of the bridge.

Another object of the invention is to provide a toggle spring oryielding support for a ponton bridge, which will enable the extension ofcontinuous balk or flooring of the floating portion of the bridge fromthe last ponton to the first trestle transom at each end of the bridge,by yielding vertically and thus reducing the slope of the roadway andthereby preventing the overstressing of the balk in the last span andalso providing the necessary articulation between the continuous pontonend span of balk and the first trestle span of balk.

With the above and other objects and advantages in view the inventionconsists of certain features of construction and operation of parts,which will hereinafter be described and shown in the accompanyingdrawings, in which:

Fig. 1 is a side elevation of the invention applied between a transomadjustably mounted on columns at one end of the floating portion of aponton bridge and a load carrying bridg floorsupporting beam mounted forup and down movement on the columns, with bumper carrying bracketsadjustably mounted on the columns for limiting the downward movement ofthe floorsupporting beam and means for limiting the upward movementthereof;

Fig. 2 is a longitudinal sectional view taken on line II-lI of Fig. 1;

Fig. 3 is an enlarged fragmentary side elevation of the left end portionof Fig. land illustrating the invention in full lines and other parts ofth supporting trestle of the ponton bridge in broken lines;

Fig. 4 is a vertical sectional view taken on line IV--IV of Fig. 1;

Fig. 5 is another vertical sectional view taken on line VV of Fig. 1;

Fig. 6 is an enlarged detail vertical sectional view through a bottomroller, track and connected parts used in carrying out the invention;

Fig. 7 is an enlarged side elevation of a bumper carrying bracket forlimiting the downward Fig. 10 is a fragmentary detail view of the lowerend of the bumper carrying bracket;

Fig. 11 is an enlarged vertical sectional detail view taken on lineXI-XI of Fig. 3;

Fig. 12 is an enlarged vertical sectional detail view taken on lineXlI-X[I of Fig. 1;

Fig. 13 is a diagrammatic view illustrating the invention applied onorieend of a ponton bridge at the point where the floating portion ofthe bridge connects to a fixed portion or approach" nearthe riverbank.,7

Fig. 14 is a schematic view showing a typical floating bridge sectionand trestle supported'shore connection.

Referring to the drawings; t eini'pidvedtran' som assembly is designatedgenerally by A andjs adapted. for use on one or more or the trestles ateach end of the bridge. The transom assembly trestle 5 adjoining the endof the floatingpor- I tion 6 of the ponton bridge 1, Fig. l3. Theheightof the transom 2 on the vertical column 4 may be adjusted to meetchanges'of water level,'or otherwise to alterthe elevation "of thetrestle bridge floor, by means of chain hoists, for exampleg'or similardevices well known in the art, attached to the tops of columns '4 and tothe ends of the transom 2. Typical hoisting means are described at pages5 to 9 of War DepartmentTeichnical' Manual :TM5-276, Octber"19,-1943,entitled Ten-ton trestle bridge. The yieldirig support includes an uppertransversely extending supporting beam 8 movably mounted onthe columns 4by means of guide brackets 9 'onits'ends and having a balk adapter I0having longitudinal balk or floor members I I mounted thereon. The balkadapter It] consists of dual swivelpipes lzf-Fig' shl and 5, which'extend'transvers'el'y in spaced parallel relation on the supportingbeam-8 an'd ar'eheld in their spaced relation by mea s or suitablyspaced tie angle members [3. The's'wivel pipes I2 are provided withcollars I'4 attheir'endS 'a'nd have a plurality of bearings larrahged'in 'spaced relation thereon, which bearings l5 are providedwithth' tie angle members [3 which'ar welded or otherwise connected tothe upper surface of the supporting beamB- Interposed betweenthelower'beam l and the upper supporting beam 8 is a transverselyextending and contracting mechanism -'or"spring'*oper-' ated toggleindicated generally by B of the yielding support and consists of asuitable number of intermediate diagonal pivot arms or levers l1, ll andll" of equal lengths and 'formediritg pairs providing lazy tongs withthe pairs of intermediate levers crossing 'each 'otherfa't their medialpoints and pivotally connected in spaced relation at these points byintermediatepivotpins l8 illustrated in detail inFig.'11. I Onebf eachpair of the end link arms {Band 19" of thelaiy tongs at one of theirends arepivoted in spaced relation by means of end pivot pins 20illustrated in detail, Fig. 12. The intermed ate-" ivotpins l8 extendtransversely with respecttb""tl'ie'iipper and lower beams 'l-"and8rspectivelyfwith 'the end pivot pins 20 extending parallel to and in thesam plane as the intermediate pivot pins l8.

The upper ends of the intermediate link arms H are pivotally connectedin spaced relation by a pivot pin 2| to a bracket 22 mounted on thelower side and at the middle of the upper beam 8 and the lowerends ofthe levers 1"! are pivotally connected in spaced relation 'by a pivotpin 23 to a bracket 24 mounted on the upper side and at :tne middle ofthe lower beam l of transom 2, ,Figs. land fl, each of the pivot pins l8forming them-crummy each pair of crossed levers. lower ends oi'thelevers i1, i1" and 19 have lower The rollers 25 mounted thereon, whichengage in tracksremained-dame upper side and extending longitudinally ofthe lower beam l and the upper ends or levers l1, l1 and end levers l9have upper ro'lle'rs 21 provided thereon, which engage in trackstflmounted on the lower side of and extending longitudinally of the upperbeam 8; Figs. '1 and 5. Trie -rollers 2'! engaging the upper 'tracks'idare mouhtedon the upperends of the link arms in thesame manner astherollers 25 on the lower ends of the -'link"arms engaging thelowertrajcks '26 as shown in enlarged detail of a roller 25'01'1 thelower track, Fig. 6, wherein the ends of a roller shaft 29 are reducedindiariieter and threaded-for receiving nuts so which retain the loweends of the link "arms'on the roller shaft 29, I V

The-intermediate and end'pivot ins -I 8 alndflfl, respectively,areelongatdffo c6nne'ctingtension springs 3| jther eto at each 'endth'ereof, which tensitn spiing's -'3 I extend in Horizontal alignmentends 'therebf, and on the outer erids '-'of the sleeves "are plates 38for holding one end "Of a spring on the -c'ollars"36. he-sew pivot'pins2'0 are identical with 'the' int'err'r'iediate' pivot-pins i la exceptthat the "states 34 6h the reduced "end 1 'ornonsj 32" exterlding'ffointhe interni'e'diate ene r-retur ihe g s ia xsn in lfi x F rkinlen h:thenh ve of the intermediatepijfot pins l'e, alsothe collars 3'61 on the endpivot' 'pin's i iiare isliortrin length than; the centres Gbn'theintermediate pivot I8 and there are ribrings the collars 36 be- Call S eeach collaar 'iiiiifhasfcinlyfbiie end of a tension spr ng-[s lconneote'df'the'rto,with the plates as frno i teuj n' tne ncs ef thesev'es 34' nora- "e d: f 'n me b it s' 'if i The columns" 'areproviddwithbumper memb'e'rs indicate ei all'y by C as moreparticularlyillustratedin eruargg utanm Figs. 7 to in inclusive. 'Eachfof;tlietemper-members C'co'nsists of -a "bracket f3}! "adjustafbly mounted on acolumn 4 andjhaving "clamping iqriefnbers 4O hinge t j ii s *a: betweentwohirigdpla'te s '42 onthe ipp'era wee-a ias, or the 'biacketfw'ith thefree ends efcla'mpir'ig hieinibers "being where the free ends of theclamping members are detachably held by means of nuts 44 mounted on thethreaded ends of the clamping members. In Fig. 10, which shows afragmentary lower end of the bracket, the clamping member 40 is removedfrom the hinge plates 42. A chain 45 is connected at one end to theupper end and on the outer side of the bracket 39 and has a pin 46connected at its other end, which is adapted to be placed through avertically extending slot 41 formed in the bracket 39 and to entersuitably spaced vertically arranged holes 48, Fig 1, provided in thecolumns 4 for adjusting the bumper bracket 35 on the columns. n theinner side of the bracket 39 is :a reinforcing rib 49 having a. bumperblock 50 suitably mounted on the upper end thereof. A bumper block ismounted on the bottom of, and at each end of the upper beam 8, Figs. 1and 2, which bumper blocks 5| are positioned above the bumper blocks 50on the upper ends of the reinforcing ribs 49 of the brackets 39. Chains52 are each connected at one end to a lift pin 53 adapted to be insertedthrough apertures formed in angle clips 54 mounted on the bottom of andadjacent to the ends of the upper beam 8. The other ends of chains 52are connected to pins 55 on angle clips 56 mounted on the bottom beam Iat its ends.

In the construction of the bridge support, the balk or longitudinalfloor members I I of the ponton bridge are connected to the balk adapter[0 which provides not only the balk connectors, but also the necessaryarticulation as the support yields vertically under the passage ofvehicles or other loads such as troops. The load is carried onto thesupporting beam 8, which distributes the vertical reaction to upperinterconnecting points of the link arms of the toggles, the center onesI l of which are fixed by a pin 2| to the bracket 22 on the supportingbeam 8, while the other upper interconnecting points of the toggles arefree to move against the action of springs Si laterally in oppositedirections on the upper rollers 27 as the support yields vertically. Thehorizontal components of the several vertical load reactions are carriedfrom the diagonal toggle members through the pivot pins l8 and 20 to thehorizontally arranged tension springs 3| which provide yieldingresistance to the load reaction. The vertical components of the severalload reactions are carried by the lower interconnecting points of thelink arms of the toggles, the center ones ll of which are fixed by a pin23 to the bracket 24 on the lower beam I, while the other lowerinterconnecting points of the toggles are free to move against theaction of the springs 3i laterally in opposite directions on the lowerrollers 25 from the pin 23. The load reactions are transmitted from thelower beam I to the transom 2 through the transom adapters 3. Theyielding support is limited in its vertical upward movement by means ofthe restraining chains 52 and in its downward movement by means of thebumper members 50 and 5|.

It will thus be seen that this invention provides a novel and eflicientform of yielding support for the shore connection of ponton bridgeswhich is well adapted for the purpose intended. Even though there hasherein been shown and described the invention as comprising certainfeatures of construction and operation of parts, it is nevertheless tobe understood that various changes may be made therein, if the changesdo not depart from the spirit or scope of the claims.

.Having thus described my invention, what I a. claim as new and wish tosecure by Letters Patent is:

1. A floating bridge structure comprising in combination, a fixedlysupported lower beam, an upper beam adapted to support a load andmounted to move vertically relative to said lower beam, a yieldingsupport connectin said lower beam with said upper beam, said yieldingsupport comprising a lazy tong lever system laterally expandablerelative to said structure comprising a series of diagonal leverspivoted together intermediate their lengths and at their ends, thecenter pivots thereof being joined to each other by tensional springsresisting lateral expansion of said system, the knuckles formed by theend pivots of one side of said system being adapted to sustain saidupper beam and the knuckles formed by the end pivots of the oppositeside being adapted to be sustained by said lower beam, for permittingvertical movement of said upper beam relative to said lower beam upon aload being applied to said upper beam, flexible restraining membersconnected to said upper and lower beams for limiting the upward verticalmovement of said upper beam and means for limiting the vertical downwardmovement of said upper beam.

2. A floating bridge structure comprising in combination, columns, alower beam fixedly supported on said columns, an upper beam adapted tosupport a load and mounted to move vertically on said columns relativeto said lower beam, at yielding support connecting said lower beam withsaid upper beam, said yielding support comprising a lazy tong leversystem laterally expandable relative to said structure comprisingaseries of diagonal levers pivoted together intermediate their lengthsand at their ends, the center pivots thereof being joined to each otherby tensional springs resisting lateral expansion of said system, theknuckles formed by the end pivots of one side of said system beingadapted to sustain said upper beam and the knuckles formed by the endpivots of the opposite side being adapted to be sustained by said lowerbeam, for permitting vertical movement of said upper beam relative tosaid lower beam upon a load being applied to said upper beam, chainsconnected to said upper and lower beams for limiting the upward verticalmovement of said upper beams and bumpers mounted on said columns andupper beam for limiting the downward movement of said upper beam.

3. A floating bridge structure comprising collumns, a transom secured tosaid columns, a fixed bridge portion, a floating bridge portionconnected to said fixed bridge portion above said transome and ayielding support mounted on said transom at the connecting point of saidfloating bridge portion and said fixed bridge portion, said yieldingsupport including a lower beam mounted on said transom, an upper beamadapted to support a load and mounted to move vertically on said columnsrelative to said lower beam, an expandin and contracting mechanismarranged between said upper and lower beams, said expanding andcontracting mechanism including a series of levers having upper andlower ends pivoted together and formed into pairs, said pairs of leverscrossing each other at their medial points, pivot pins connecting saidpins of said levers together in spaced relation at their medial pointsand pivot pins connecting one of the ends of each pair of end leverstogether in spaced relation,

, said upper ends of the middle levers pivoted to acme/i3 saia opp'er:beam and said abwer ends or other middle levers pivoted to said lowerbeam, rmiers carriedzonmhevotlrerrupper endsaof safd'levers andengagingasaid upper ibeanr, rollers eanriedeonthe other lower ends ofjsaidiievers'and'zengagmgsaid lower beam and horizontally alignedtension sprin connecting said pivot pins togetherpsaid' roller carryingupper and lower ends of said-11eveis adapted to :move against the actionifi said springs laterally on :said rollersvfromsaid pivoted connectedupper and lowereends 20f said middl levers under said-upper beam andion-said low-ii beamesvsaid iupper beam yields ventically'gunder arlond.

4.: A" yielding .supportfor :a floating3hr ig.e .QQX prising incombination, a fixedlyisupported base, an upper beam thereaboveadapted-to sunpont an eccentricandvariable*loadzand mounted tomoyevertically relative to said base :While remaining parallel thereto,a lazy tongilever =-system' late rally expandable relative toy-said baseand ,beam and interposed between the same, said system comprising aseries-of-diagonal levermpivotedtogether --at their Emiddles andat theirends, the

center pivots thereof'being joined together-by tensional springsV-resisting lateral-expansion of the system, the knuckles formed by theupper endipivots of said system sustaining said loaded beam and theknuckles iformedby the JOWBIH'GIld pivots bein sustained by said base, Aeach ofsone pair -of :oppositeknuckles being epivotally connected \torsaid base and said beam trespecltively andtheremaining upper-Fahdlowenknuckles earrying'bearing-meansadapted: to bear. against said baseand beam respectively, :and cooperating:

guide means carried vby I the :baseand :beam for maintainin saidbaseandbeam in vertical alignment. 7

-5. A yielding support for a floating bridge comprising in combination,a fixedlyrsupported :base, an upper beam thereaboveadaptedto support-aneccentric and variable load-and mounted to move vertically relative to:said 'base While remaining parallel thereto, a lazy tong lever'systemlaterally=expandable relative to: said base :and :beam' Oppositeimuoklesbeing mivotaliy :eonnected 5110' said- .base anti'saidbeamrespectively-and :the remaining' upper and. lower knuckles carryingrollers'z adapted to doear againstsaLid :base and beam respectively,tracks mounted on said base "and beam engagingsaid rollerswhemthe'latteymove laterally; as said beam yields :verticallyumderaaload, cooperating :guide cmeans carried by the basezand: the beam" formaintaining saidibase and beam in vertical alignment, bumpers carricdt'by the guide means .to limit :downward xmovement of.said beam,andzflexible connections between said: base and beamltolimit upward;movementiof the latter.

-..6.'.=A ".ponton bridge structureicomprismg .in

combination; supporting c01umns,:a-.transom:fix-T edly :snpported:thereon, an ;upper :beam :above said transom adapted :to support ;a'load and mounted to; move verticallyzorrsaid columns relativei'to'saidatransom; abalk'adapter mounted'zim' said anpperabeam ifor :supporting:longitndirmt 75* 8f floamgfofia; zooniiinuous ponton .spam'mfirstiitrestlespanwfithexbridger a lazy tong-lever system izlaterallyexpandable relative to said bridge strirctmie and interposed betweensaid.

transom andzsaidimpperribeam, said system :commiis'ingmi-senies-ofini'a'gonal levers pivoted to.- gather intermediate their lengths and attheir enda the eentermpivots thereof being joined together :by:t-EDSiOZXaii springs resisting lateral expansion lofathesystem, theknuckles formed: by the iupperiiendspivotsaof said system being adapt.-

ed to said. upper beam and the knuckles formed-iiby ithe lower end.pivots beingadapted to be: sustained by said transom, each of one pairof iopposite knucklesxbeing pivotally connected tossrid anansomandosaidbeam respectively, and:

meansaonssaidi balkxadapterzzfor connecting the longitudinal flooringithereto endprovidinganticulationcbetween thezcontinuous end span andthe firstitnestle span oaths-bridge.

A-yieldingeupportfor a floating bridgecomprising :in :combmation,...atransom fixedly..isup ported byiwertical moiumns, van beam slid,- ablymounted on saiclcolumns abovesaidtran: som::gandi=.-adapted to supportan eccentric and varyinguioadaaslazy i-.tong.vlever system lateraliyexpandable lelatine 'ItO sm'd transom and beam. and interposed betweenthe same, said system compnisingia seriemofizdiagonal levers@pivotedrtogather intermediate: their. lengths and: at their ends, the-center aivots thereof being joined togetherzby ztensionalzspringsresisting zlatemlaaxpansiorr or ithe system; the knuckles formed(by thezunper pivots of said system being adapted to: sustain saidmovablezbeam .andzthe ak nuckles formed by-ithe lower-end lpivots beingadapted=to:be sustainedzbyzsaid transom;eachotoneapairiofoppositezsknuckles being; pivotally conneoted to saidtransom-: and saidtbeam respectively and the remaining upper: andlQWEIikDUCklGS carryingbeaning means-adapted to-bearwagainstsaid transomand beam respectively, atracks mounted on'said transom zand:beamzengaging said bearings means as-theilatterrmove:laterallywhensaidbeam' yields veiztically'mndereailoadpand means to limit :both

downward and mpii ard movement .of said beam.

18.- ,Res l1ient supporting structure for supporting anditransm ttinaanableloa s, w ch c mpris s, inicombmation, a-.-mova-b1e loadsupp rtingm mbcrsa-nd fi1i3 Qn@ yLh3S mem er. and r s n meansinterposed betweenand connected to the load supporting member and :to the .base memberandmaintainimz these members substantially parallelfithe said::resilientmeans comprising a lazy tcn-g dever system yieldable under variableloads iapplied ;to':any portion of the movable :load supporting :member:for enabling movement of thedoad supporting member EtOVZIdS the basemember -under:the zforcerof a load applied thereto-;:the.:lany tongleversystem including aseries of rdiagonali-levers :centrally :pivoted:together at theinends, and tensionalsprings; interconnecting thecenterlpivots of ithe ilevers and resistinglateral expansion of the saidlevers,.the end pivots ofronelsid'esof the 'lever systemcontacting themovableaload supporting member and defining knuoklesmiaptedi to sustainthe: said: movable load supportingemember; :the end :pivots of the.oppositeiside Qof :the lever: system.:contacting the base member andbeing. sustainedby the said base member.

J9. loadesupporting'; and transmitting istructare; which comprises. a:movable load supporting member sand :'a -:stationary base a member-towards Which .nthe' cmovable (load supportingamembemis moved by theforce of a variable load applied to any portion of the surface thereof,a lazy tong lever system interconnecting the load supporting member andthe base member, the said lazy tong lever system including a series oflaterally expandable diagonal levers pivoted together centrally and attheir ends, tensional springs interconnecting the center pivots of thelevers and resisting lateral expansion of the lever system, the endpivots of one side of the lever system forming pivotal connectingknuckles with the movable load supporting member which knuckles sustainthe said load supporting member, end pivots of the opposite side of thelever system forming pivotal connecting knuckles with the base memberand being sustained by the base member, and guide instrumentalitiesinterconnecting the movable load carrying member and the base member andincluding upright guide means mounted on the base member and guidebrackets mounted on the load carrying member extending around theupright guide means for maintaining the load carrying member and basemember in alignment.

10. A load supporting and transmitting structure which comprises. incombination, a movable load supporting member and a stationary basetowards which the movable load supporting member is moved by the forceof a variable load applied to any portion of the surface thereof, a lazytong lever system interconnecting the load supporting member and thebase member, the lever system including a series of laterally expandablediagonal levers pivotally connected together centrally and at theirends, tensional springs interconnecting the center pivots of the leversand resisting the lateral expansion of the said system, the end pivotsof one side of the lever system forming pivotal connecting knuckles withthe movable load supporting member, which knuckles sustain the loadsupporting member, end pivots of the opposite side of the lever systemforming pivotal connecting knuckles with the base member and beingsustained by the base member, guide instrumentalities interconnectingthe movable load carrying member and including vertically disposedguide-standard means mounted on the base member and guide bracketsmounted on the load carrying member and extending around the verticallydisposed guide-standard means for maintaining the load carrying memberand base member in alignment, and bumper means carried by the verticallydisposed guidestandard means for limiting motion of the load carryingmember toward the said base member.

11. A load supporting and transmitting structure which comprises, incombination, a movable load carrying member and a stationary base membertowards which the movable load carrying member is moved by the force ofa variable load applied to any portion of the surface thereof, a lazytong lever system interconnecting the load carrying member and the basemember, the lazy tong lever system including a series of laterallyexpandable diagonal levers pivotally connected centrally thereof and attheir ends, torsional springs interconnecting the center pivots of thelever and resisting the lateral expansion of the said system, the endpivots of one side of the lever system forming pivotal connectingknuckles with the movable load carrying member,

which knuckles sustain the load carrying mem-- ber, end pivots of theopposite side of the lever system forming pivotal connecting knuckleswith the base member and being sustained by the base ('10 member, guideinstr'umentalities interconnecting the movable load carrying member andthe base member and including vertically disposed guide standard means,and guide brackets mounted on the load carrying member extending aroundthe vertically disposed guide standard means for maintaining the loadcarrying member and the base member in alignment, bumper means mountedon the said guide standard means for limiting motion of the loadcarrying member towards the base member, and flexible restraining meansinterconnecting the load carrying member and the base member forlimiting motion of the load carrying member.

12. A load supporting and transmitting structure which comprises, incombination, a movable load carrying member and a stationary base membertowards which the movable load carrying member is moved by the force ofa variable load applied to any portion of the surface thereof, a lazytong lever system interconnecting the load carrying member and the basemember, the lever system including a series of laterally expandablediagonal levers pivotally connected centrally thereof and at their ends,torsional springs interconnecting the center pivots of the levers andresisting the lateral expansion of the said system, end pivots of oneside of the lever system forming pivotal connecting knuckles with themovable load carrying member, which knuckles sustain the load carryingmember, end pivots of the opposite side of the lever system formingpivotal connecting knuckles with the base member and being sustained bythe base member, cooperating guide instrumentalities intercomnecting themovable load carrying member and the base member for maintaining theload carrying member and the base member in alignment, means carried bythe base member for limiting movement of the load carrying member towardthe base member, and flexible means interconnecting the load carryingmember and the base member for limiting movement of the load carryingmember away from the base member.

13. A load supporting and transmitting structure which comprises, incombination. a movable load carrying beam, and a stationary base membertowards which the beam is moved by the force of a variable load appliedto any portion thereof, a lazy tong lever system interconnecting thebeam and base member, the lever system including a series of laterallyexpandable diagonal levers pivotally connected centrally thereof and attheir ends, torsional springs interconnecting the center pivots of thelevers and resisting the lateral expansion of the lever system, endpivots of one side of the lever system forming pivotal connectingknuckles with the said beam. which knuckles sustain the beam. end pivotsof the opposite side of the lever system forming pivotal connectingknuckles with the base member and being sustained by the base member.bearing means carried by end pivotal connections of diagonal leversintermediate the end levers of the system, certain of the bearing meansbearing against and supporting the said beam and others of the saidbearing means bearing against and being supported by the said basemember, guide means carried by the base member and the beam andcooperating to maintain the said beam and base member in verticalalignment, means carried by the base member for limiting downwardmovement of the beam, and flexible means interconnecting the beam andbase member for limiting upward movement of the beam.

enema l4; :A load supporting and transmitting -struc--- ture comprisingera :movable-Joad earrylng member and a/ relatively stationary basetoward which the-load earryinggmember is 'moved :by the force or .evariable loadiapplied lto any -portion =of the surface thereoflrand wlazy -tongdever system interconnecting the loed carrying member-and thebase and including: .a :plurality ot diagonal levers pivotellyinterconnected at their centers andends, andlbe'mgclatma-lly expandable;sand tensional springs interconnected i at: the-center pivots'of theleversandlresistinglaterelexpansion or the lsaid levers, end ipivots 'of-One :side-ofithe lever system forming sustainmgknuckles-engaging themovable load earryi-ng member for sustaining.- the same; end v-pivotsiofi-the. opposite side of the leversystem engaging-the base and beingsustainedbythesaid base.

'15. -A load supportingand transmitting strueture comprisinga movableload=carrying member and -a stationary base --towarde which 'the loa-dcarrying member is. moved -=by theforce of a variablelload appliedltoanysportion either-surface oitbe load-carrying member, st-lazy tonglever system engaging the load marrying member and the stationarybaseand i-eomprising a, series of diagonal levers pivoteditegethereezxtrallyand at their ends, tensional springs iinteseonnecting thecenter EPiVOtS of: the. lever system and :resisfing lateral expansion oithe lever System, the end pivotsoi oneside -of the lever system formingknuckles engaging and sustaining the movable load fcarrying member,endipivots on the opposite side-efthe lever system being engaged by thebase and :sustained' thereby, and guide means on the load earryingmember and on the base for maintaining-the load carrying member and [thebase-inverticalalignment. =10

JOHN W. BERETTA.

REFERENCES CITED Thefollowing-referencesare of record in the fife ofthis patent:

GT-HER REFERENCES 'WarDepartment Manual TM-'5'276, October 13,1943.('COpy in 14-27;)

